{"id":"F2006L02991","name":"AD/B737/29 Amdt 2 - Window Belt Skin Doubler","slug":"ad-b737-29-amdt-2-window-belt-skin-doubler","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":60275,"registerId":"commonwealth-F2006L02991-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 737 Series Aeroplanes","sectionType":"division","heading":"Boeing 737 Series Aeroplanes","content":"### Boeing 737 Series Aeroplanes\n\n| AD/B737/29 Amdt 2 | Window Belt Skin Doubler | 10/2006 |\n| ----------------- | ------------------------ | ------- |\n\n| Applicability: | Model 737 series with line numbers 001 through 519.                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the Technical Requirements of FAA AD 91-07-04Amdt 39-6933.Note: Boeing Service Bulletin 737-53-1078 Revision 4 refers. The FAA has approved the inspection and repair procedures contained in this service bulletin as an alternative to the earlier service bulletin issue specified in AD 91-07-04.                                                                                                                                                                                             |\n| Compliance:    | As specified in the Requirement document, with a revised effective date of13 June 1991.The compliance effective date remains unchanged by this issue.                                                                                                                                                                                                                                                                                                                                                                       |\n|                | This Amendment becomes effective on 28 September 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n| Background:    | The FAA received reports that were submitted as a result of FAA AD 89-15-05, which indicated that approximately one-third of the aircraft inspected had disbonding. This condition, if not corrected, could result in rapid decompression of the aircraft. This Directive requires repetitive inspections until the terminating modification is accomplished.Amendment 2 is issued to introduce a Requirement note that specifies FAA approval of work accomplishment in accordance with the latest service bulletin issue. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n28 July 2006","sortOrder":0},{"sectionNumber":"AD/B737/29 Amdt 2","sectionType":"part","heading":"AD/B737/29 Amdt 2","content":"## AD/B737/29 Amdt 2","sortOrder":1},{"sectionNumber":"Window Belt Skin Doubler","sectionType":"part","heading":"Window Belt Skin Doubler","content":"## Window Belt Skin Doubler","sortOrder":2},{"sectionNumber":"10/2006","sectionType":"part","heading":"10/2006","content":"## 10/2006","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"Amendment 2 adds a Requirement note specifying FAA approval of accomplishment in accordance with the latest Boeing Service Bulletin issue (737-53-1078 Revision 4) as an alternative to the earlier service bulletin referenced in FAA AD 91-07-04. The amendment does not change the affected fleet (line numbers 001–519) or the compliance effective date (13 June 1991); it only clarifies/expands permitted repair procedures with FAA approval."},"complexity_factors":["Cross-reference to external FAA AD 91-07-04 and Boeing Service Bulletin 737-53-1078 Rev 4 (external-document dependency).","Technical inspection and repair requirements for structural failure risk (disbonding leading to possible rapid decompression).","Applicability limited to specific line numbers (001–519), requiring verification of serials for applicability.","Repetitive inspection regime until a terminating modification is accomplished (ongoing operational burden).","Dual effective dates: compliance effective date retained (13 June 1991) while this amendment is effective 28 September 2006 (administrative clarity needed).","Amendment introduces an FAA-approval note as an alternative method, creating interaction between regulator approvals and operator choices.","Recordkeeping, maintenance scheduling and repair-cost implications for operators and maintenance organisations."],"plain_english_summary":"This directive requires operators of Boeing 737 series aeroplanes (line numbers 001–519) to perform repetitive inspections and repairs for window-belt skin disbonding under the technical requirements of FAA AD 91‑07‑04 and permits FAA‑approved procedures in Boeing Service Bulletin 737‑53‑1078 Revision 4 as an alternative (Requirement). Operators pay for inspections and repairs and must keep inspecting until a terminating modification is done. Amendment 2 adds the FAA‑approval note; the compliance effective date remains 13 June 1991."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope of the airworthiness directive. Amendment 2 does not expand the applicability to new aircraft models or introduce new safety requirements. It merely updates the compliance method to recognize a newer version of the referenced Boeing service bulletin, which is a routine administrative update typical of aviation safety maintenance."},"complexity_factors":["Short, single-purpose document (approximately 250 words)","Only 1 defined applicability criterion (line numbers 001-519)","Heavy reliance on external documents (FAA AD 91-07-04 and Boeing Service Bulletin 737-53-1078) — the actual technical requirements are not reproduced in the text","Simple amendment structure: adds one note about alternative compliance method","No nested conditional logic or exceptions within the text itself","Technical aviation terminology assumes specialized knowledge (e.g., \"window belt skin doubler,\" \"disbonding,\" \"terminating modification\")"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of early Boeing 737s (line numbers 001–519) to perform repetitive inspections and necessary repairs of the window belt skin doubler because FAA findings showed widespread disbonding that can lead to rapid decompression. \n\nIt keeps existing inspection/repair requirements tied to FAA AD 91-07-04 and Boeing Service Bulletin 737-53-1078, and amends the AD to permit using Revision 4 of that service bulletin."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-29-amdt-2-window-belt-skin-doubler","history":"/api/acts/ad-b737-29-amdt-2-window-belt-skin-doubler/history","analysis":"/api/acts/ad-b737-29-amdt-2-window-belt-skin-doubler/analysis","conflicts":"/api/acts/ad-b737-29-amdt-2-window-belt-skin-doubler/conflicts","importantCases":"/api/acts/ad-b737-29-amdt-2-window-belt-skin-doubler/important-cases","documents":"/api/acts/ad-b737-29-amdt-2-window-belt-skin-doubler/documents"}}